Alfven wave dissipation in the solar chromosphere
Alfven wave dissipation in the solar chromosphere
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DOI：
10.1038/s41567-018-0058-3
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发表时间：
2018-05-01
期刊：
影响因子：
19.6
通讯作者：
Hewitt, Rebecca L.
中科院分区：
文献类型：
--
作者：
Grant, Samuel D. T.;Jess, David B.;Hewitt, Rebecca L.
半个多世纪以来，磁流体阿尔芬波（1）一直是实验室等离子体物理（2）和天体物理（3）的焦点。它们独特的性质使它们成为理想的能量传输者，虽然太阳大气层为它们的存在提供了有利条件，但由于它们不断演变和动态的观测特征，直接探测已被证明是困难的。阿尔芬波作为一种加热机制的可行性依赖于波能的有效耗散和热化，直到现在还没有直接的证据。在这里，我们提供了第一个观测证据阿尔芬波加热色球等离子体在太阳黑子本影通过形成冲击锋。激波环境的磁场结构，以及切向速度特征，使它们与传统的本影闪光区别开来（5）。所观察到的局部温度提高5%是一致的模式转换阿尔芬波驱动向上传播的磁声振荡的耗散，提供了前所未有的洞察阿尔芬波在太阳大气中的行为和超越。
Magnetohydrodynamic Alfven waves(1) have been a focus of laboratory plasma physics(2) and astrophysics(3) for over half a century. Their unique nature makes them ideal energy transporters, and while the solar atmosphere provides preferential conditions for their existence(4), direct detection has proved difficult as a result of their evolving and dynamic observational signatures. The viability of Alfven waves as a heating mechanism relies upon the efficient dissipation and thermalization of the wave energy, with direct evidence remaining elusive until now. Here we provide the first observational evidence of Alfven waves heating chromospheric plasma in a sunspot umbra through the formation of shock fronts. The magnetic field configuration of the shock environment, alongside the tangential velocity signatures, distinguish them from conventional umbral flashes(5). Observed local temperature enhancements of 5% are consistent with the dissipation of mode-converted Alfven waves driven by upwardly propagating magneto-acoustic oscillations, providing an unprecedented insight into the behaviour of Alfven waves in the solar atmosphere and beyond.